A circuit system is described, for example, in U.S. Pat. No. 5,499,186 A. The circuit system of this patent shows at least two half-bridges per phase.
In voltage converters, half-bridges made of switches are used in connection with a coil and a capacitor to convert a voltage into a different voltage. By switching a plurality of phases in parallel and controlling them in temporally offset fashion, the result is achieved that the load is reduced on the components, and in addition the ripple current is significantly reduced. In addition, in this way the electromagnetic compatibility is increased, and fewer losses occur, thus improving efficiency. As switches, here in most cases MOSFETs are used, which in case of error generally fail with a short circuit. In the case of a voltage converter having a plurality of phases connected in parallel, the failure of a phase results in the failure of the entire converter.